/**
 * @a https://leetcode.cn/problems/maximum-width-of-binary-tree/
 */

#include "common.h"



//Definition for a binary tree node.
struct TreeNode {
    int val;
    TreeNode *left;
    TreeNode *right;
    TreeNode() : val(0), left(nullptr), right(nullptr) {}
    TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
    TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
};

class Solution {
public:
    int widthOfBinaryTree(TreeNode* root) {
        vector<pair<TreeNode*, unsigned>> q;
        q.push_back({root, 1});
        unsigned ret = 0;
        while(q.size())
        {
            auto &[x1,y1] = q[0];
            auto &[x2,y2] = q.back();
            ret = max(ret, y2 - y1 + 1);

            vector<pair<TreeNode*, unsigned>> tmp;
            for(auto &[x,y] : q){
                if(x->left) tmp.push_back({x->left , y*2});
                if(x->right) tmp.push_back({x->right, y*2 + 1});
            }
            q = tmp;
        }
        return ret;
    }
};